Method for manufacturing secondary battery

Abstract

A method for manufacturing a secondary battery is provided. The method includes accommodating an electrode assembly in a battery case, injecting a first electrolyte composition into the battery case to impregnate the electrode assembly, injecting a second electrolyte composition into the battery case, and curing the second electrolyte composition, wherein an electrode tab is connected to the electrode assembly and protrudes to the outside of the electrode assembly, wherein the first electrolyte composition includes a 1-1st lithium salt containing at least one selected from the group consisting of lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and a first solvent, wherein the second electrolyte composition includes an oligomer and a second solvent and does not include lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI).

1 . A method for manufacturing a secondary battery, the method comprising:
 (S1) accommodating an electrode assembly in a battery case;   (S2) injecting a first electrolyte composition into the battery case to impregnate the electrode assembly;   (S3) injecting a second electrolyte composition into the battery case; and   (S4) curing the second electrolyte composition,   wherein,
 an electrode tab is connected to the electrode assembly and protrudes to an outside of the electrode assembly, 
 the first electrolyte composition includes a 1-1st lithium salt containing at least one selected from the group consisting of lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and a first solvent, and 
 the second electrolyte composition includes an oligomer and a second solvent, and 
 does not include lithium bis(fluorosulfonyl)imide (LiFSI) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). 
   
     
     
         2 . The method of  claim 1 , wherein the first electrolyte composition comprises a liquid electrolyte composition. 
     
     
         3 . The method of  claim 1 , wherein:
 the first electrolyte composition is a gel polymer electrolyte composition, and   further comprises an oligomer.   
     
     
         4 . The method of  claim 3 , wherein in the step (S4), the first electrolyte composition and the second electrolyte composition are cured together. 
     
     
         5 . The method of  claim 3 , wherein the method further comprises curing the first electrolyte composition after the step (S2). 
     
     
         6 . The method of  claim 1 , wherein the first electrolyte composition further comprises a 1-2nd lithium salt containing at least one selected from the group consisting of lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroantimonate (LiSbF 6 ), lithium tetraoxoaluminate (LiAlO 4 ), lithium tetrachloroaluminate (LiAlCl 4 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), lithium nonafluorobutanesulfonate (LiC 4 F 9 SO 3 ), lithium chloride (LiCl), lithium iodide (LiI), lithium bis(oxalato)borate (LiB(C 2 O 4 ) 2 ), lithium bis(pentafluoroethanesulfonyl)imide(LiN(C 2 F 5 SO 2 ) 2 ), lithium fluoroalkylborate (LiFAB), and lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI). 
     
     
         7 . The method of  claim 1 , wherein the second electrolyte composition further comprises a second lithium salt, wherein the second lithium salt comprises a at least one selected from the group consisting of lithium hexafluorophosphate (LiPF 6 ), lithium perchlorate (LiClO 4 ), lithium hexafluoroarsenate (LiAsF 6 ), lithium tetrafluoroborate (LiBF 4 ), lithium hexafluoroantimonate (LiSbF 6 ), lithium tetraoxoaluminate (LiAlO 4 ), lithium tetrachloroaluminate (LiAlCl 4 ), lithium trifluoromethanesulfonate (LiCF 3 SO 3 ), lithium nonafluorobutanesulfonate (LiC 4 F 9 SO 3 ), lithium chloride (LiCl), lithium iodide (LiI), lithium bis(oxalato)borate (LiB(C 2 O 4 ) 2 ), lithium bis(pentafluoroethanesulfonyl)imide (LiN(C 2 F 5 SO 2 ) 2 ), lithium fluoroalkylborate (LiFAB), and lithium 2-trifluoromethyl-4,5-dicyanoimidazole (LiTDI). 
     
     
         8 . The method of  claim 1 , wherein the oligomer comprises at least one selected from the group consisting of a fluorine-based oligomer, a polycarbonate-based oligomer, and a polysiloxane-based oligomer. 
     
     
         9 . The method of  claim 1 , wherein the second electrolyte composition further comprises an-a polymerization initiator. 
     
     
         10 . The method of  claim 1 , wherein the electrode tab comprises aluminum. 
     
     
         11 . The method of  claim 1 , wherein the first electrolyte composition is injected so as not to contact the electrode tab. 
     
     
         12 . The method of  claim 1 , wherein in the step (S3), the second electrolyte composition is injected outside of the electrode assembly. 
     
     
         13 . The method of  claim 1 , wherein,
 the first electrolyte composition is disposed inside the electrode assembly after the step (S4), and   the second electrolyte composition is cured to form a gel polymer electrolyte, wherein the gel polymer electrolyte is disposed outside the electrode assembly.   
     
     
         14 . The method of  claim 1 , wherein an electrode and a separator are alternately stacked in the electrode assembly, and an adhesive is applied to a surface of at least one of the electrode or the separator such that the electrode and the separator are bonded to each other. 
     
     
         15 . The method of  claim 14 , wherein the separator comprises a porous substrate and a ceramic coating layer disposed on both surfaces of the porous substrate, wherein the ceramic coating layer includes inorganic particles in an amount of 92 wt % or more to less than 100 wt % and a binder in an amount of greater than 0 wt % to 8 wt % or less. 
     
     
         16 . The method of  claim 14 , wherein the adhesive is applied in the form of a plurality of patterns spaced apart from each other. 
     
     
         17 . The method of  claim 14 , wherein the adhesive is dissolved in the first electrolyte composition by the injection of the first electrolyte composition. 
     
     
         18 . The method of  claim 17 , wherein a trace of the adhesive is present on the surface of the at least one of the separator or the electrode after the adhesive is dissolved. 
     
     
         19 . The method of  claim 14 , wherein,
 the electrode comprises a first electrode and a second electrode, and   the electrode assembly is manufactured by a method including:   (a) applying the adhesive on at least a portion of the separator or the first electrode;   (b) bonding the separator and the first electrode through the adhesive applied in (a);   (c) folding one side of the separator to cover the first electrode;   (d) applying the adhesive on at least a portion of the separator or the second electrode;   (e) bonding the separator and the second electrode through the adhesive applied in (d); and   (d) folding the other side of the separator to cover the second electrode.